* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
}

header {
    background: rgba(255, 255, 255, 0.95);
    padding: 1.5rem;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
}

header h1 {
    text-align: center;
    color: #2c3e50;
    font-size: 2.5rem;
    margin-bottom: 1rem;
    font-weight: 300;
}

nav {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

nav button {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 25px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    font-weight: 500;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

nav button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}

nav button:active {
    transform: translateY(0);
}

main {
    max-width: 1400px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.dashboard {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
}

.stats-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: white;
    padding: 1.5rem;
    border-radius: 15px;
    text-align: center;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
    border: 1px solid rgba(102, 126, 234, 0.1);
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

.stat-card h3 {
    color: #7f8c8d;
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.stat-number {
    font-size: 2rem;
    font-weight: bold;
    color: #2c3e50;
    margin-bottom: 0.5rem;
}

.stat-change {
    font-size: 0.8rem;
    font-weight: 600;
    padding: 0.25rem 0.5rem;
    border-radius: 12px;
}

.stat-change.positive {
    color: #27ae60;
    background: rgba(39, 174, 96, 0.1);
}

.stat-change.negative {
    color: #e74c3c;
    background: rgba(231, 76, 60, 0.1);
}

.chart-container {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    margin-bottom: 2rem;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
}

.charts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 2rem;
}

.chart-box {
    background: white;
    padding: 1.5rem;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
}

.chart-box h3 {
    color: #2c3e50;
    margin-bottom: 1rem;
    font-weight: 500;
    text-align: center;
}

footer {
    background: rgba(255, 255, 255, 0.95);
    text-align: center;
    padding: 1.5rem;
    margin-top: 2rem;
    color: #7f8c8d;
    backdrop-filter: blur(10px);
}

/* 响应式设计 */
@media (max-width: 768px) {
    header h1 {
        font-size: 1.8rem;
    }
    
    nav {
        gap: 0.5rem;
    }
    
    nav button {
        padding: 0.5rem 1rem;
        font-size: 0.8rem;
    }
    
    .dashboard {
        padding: 1rem;
    }
    
    .stats-container {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
        gap: 1rem;
    }
    
    .charts-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .stat-number {
        font-size: 1.5rem;
    }
}

@media (max-width: 480px) {
    .stats-container {
        grid-template-columns: 1fr 1fr;
    }
    
    main {
        margin: 1rem auto;
    }
}

/* 动画效果 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.stat-card,
.chart-container,
.chart-box {
    animation: fadeInUp 0.6s ease-out;
}

.stat-card:nth-child(1) { animation-delay: 0.1s; }
.stat-card:nth-child(2) { animation-delay: 0.2s; }
.stat-card:nth-child(3) { animation-delay: 0.3s; }
.stat-card:nth-child(4) { animation-delay: 0.4s; }

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: rgba(255, 255, 255, 0.1);
}

::-webkit-scrollbar-thumb {
    background: rgba(102, 126, 234, 0.5);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(102, 126, 234, 0.7);
}